Arrangement for igniting two or more gas- or vapor-filled main discharge tubes



1952 K D. FORTUYN ,617,081

ARRANGEMENT FOR IGNITING TWO OR MORE GAS-OR VAPOR-FILLED MAIN DISCHARGE TUBES Filed NOV. 23, 1951 INVENTOR Koenrood Droogleey Fortyyn j Agent Patented Nov. 4, 1952 ARRANGEMENT FOR IGNITING TWO OR MORE GAS- OR VAPOR-FILLED MAIN DISCHARGE TUBES Koenraad Droogleever Fortuyn, Eindhoven, Netherlands, assignor to Hartford National Bank and Trust Company, Hartford, Conn., as trustee Application November 23, 1951, Serial No. 257,744 In the Netherlands December 13, 1950 '7 Claims. 1

This invention relates to an arrangement for igniting two or more gasor vapour-filled main discharge tubes having a cold, for example, mercury cathode, each tube provided with an immersed ignition electrode, in which of the two types of ignition members the corresponding ones are directly or indirectly interconnected, each ignition circuit including a source of ignition voltage and a separate, controllable gasor vapour-filled auxiliary discharge path for determining the instant of ignition, and the discharge paths of each ignition circuit being united into a single multi-anode discharge tube having a single cathode. The term two types of ignition members is to be understood to mean on the one hand the immersed ignition electrodes and on the other hand the associated cold cathodes. Since the multi-anode auxiliary discharge tube has a single cathode, the use of coupling transformers between the anode circuits of this tube and the control circuits of the main discharge tubes is necessary for the transmission of the control voltages for separating the individual ignition circuits of the main discharge tubes. Furthermore, this usually requires a number of dry or wet rectifier elements in the ignition circuit to prevent the flow of return current through the ignition electrode, since the coupling transformers secondarily supply an alternating voltage to the ignition circuit.

Since the ignition currents and ignition voltages of the said main discharge tubes are comparatively high, appropriate rectifier elements must be used. This requires the use of large elements which are comparatively expensive and, moreover, not always reliable in operation.

This disadvantage is mitigated by the invention, according to which these rectifier elements may be eliminated so that a high degree of oprational reliability is obtained.

According to the invention, in an arrangement of the aforesaid type, each ignition circuit comprises a separate transformer, one winding of which is connected in the anode lead and the other winding, which is connected in series therewith, is inserted in the cathode lead of each auxiliary discharge path such that upon the passage of current the total impedance of the two windings is different from, preferably smaller than, the impedance of one of the two windings.

Upon breakdown of an auxiliary discharge path, the source of ignition voltage will cause a current to flow through the ignition circuit concerned. Since the two transformer windings are connected in series in the same ignition circuit,

a connection may be made in which the ampereturns of the windings are oppositely directed with respect to each other. In this case, the transformation ratio is preferably at least approximately 1: 1, since the compensation is then practically complete. As the total impedance of the two windings may consequently be chosen much lower than the impedance of one of the windings, only this ignition circuit will carry a sufficient current to ensure ignition of the main discharge tube concerned. Due to the much greater impedance of the remaining transformers, the current carried off through the common lead of ignition members of the same name cannot acquire such a value as to bring about ignition of another main discharge tube.

Consequently, in the arrangement according to the invention, the transformers fundamentally do not act as such, so that no secondary alternating voltage whose undesirable action must be prevented by means of additional rectifiers in the ignition circuits is supplied, as is the case in the aforesaid known arrangements. In the present case the transformers only act as automatically operating devices which, according to convenience, have a high or low impedance, i. e., a self-regulating impedance value.

According to the further invention the ignition circuits include transformers, whose magnetic circuits are saturated to a greater or less degree on the passage of current. Since also in this case the total impedance of the transformer has relatively much decreased, because the remaining transformers are not saturated, the path through the other transformers will now also be cut off to a greater or less degree. The two windings of the saturated transformer will only have a low impedance. In this event, the ampereturns of the two transformer windings need not necessarily be oppositely directed.

In order that the invention may be more clearly understood and readily carried into effect, it will now be described more fully with reference to the accompanying drawing representing diagrammatically several examples thereof, and in which:

Fig. 1 shows three gasor vapor-filled main discharge tubes l, 2, 3, which may, for example, be connected as a rectifier and comprise cathodes 4, 5, 6 and immersed ignition electrodes 1, 8, 9, constituting the aforesaid two types of ignition members. The cathodes are interconnected. The ignition circuits comprise sources of ignition voltages in the form of charge capacitors IO, H, 12 and controllable gasor vapor-filled main discharge paths l3, i4, i5. These auxiliary discharge paths having separate anodes it, ii, I8 and associated control members i9, 2t, 2! are united into a single multi-anode discharge tube 22 having a common cathode 23.

According to the invention each ignition circuit comprises separate transformers 2d, 25, 2s, one winding of which (27, 28, 29) is connected in the anode lead and the other winding (3t, 3!, 32) is connected, in series therewith, in the cathode lead of each auxiliary discharge path (i3, I4, I5) with respect to the loads Ii, 'i5, 8-6, 9 (the ignition members). If, for example, the auxiliary discharge path is is rendered conductive by supplying a voltage impulse to the control member I 9, the voltage across the'capacitor it will cause an electron current to flow through winding 21, cathode 4, ignition electrode 7, winding and back to the cathode 23 of the auxiliary discharge tube 22.

If the ampere-turns of the windings 2'! and as are oppositely directed and the transformation ratio is approximately 1:1, the impedance which wouldoccur if only winding 2? is loaded with current is almost completely compensated for, so that 1 the current will pass the said ignition circuit with a, low resistance. The current flowing from winding 21. through the common cathode lead of the main discharge tubes, the cathodes 5, t the ignition electrodesfi, 9 and the windings 35,32 back to the cathode 23 of the auxiliary discharge tube is reduced to a; low inoffensive magnetization currentstrength, since due to the currentless windings 28 and 29 (the auxiliary discharge paths id and I5 not conductive) the impedances'25 and 26 will have a relatively high value.

If the iron-circuit of transformers 2d, 25, 23 is so proportioned as to be saturated as a result of the passage of current through the winding connected to the condenser (when the capacitor becomes discharged), it fundamentally is not necessary for the ampere-turns of the two windings of each transformer to be oppositely directed or for the transformation ratio to be 1:1. Due to saturation of the iron-circuit of the transformer concerned the impedance of the two windings will only be low, whereas the nonsaturated transformers automatically prevent any undesirable passage of current.

In Fig. 1, the capacitors H H, l2 need not necessarily be charged with direct voltage. When charging with alternating voltage it is in general necessary for the discharge to occur at an instant at which'the anode concerned of the auxiliary discharge paths is positive.

After the main discharge tube i has been struck and the capacitor if has been discharged,

In this case, the capacitor is charged with direct voltage and discharged at a threefold frequency. Otherwise, this arrangement operates similarly to that shown in Fig. 1. As an alternative, the

capacitor 33 may be inserted in the common cathode lead of the auxiliary discharge tube 22 as shown in dash lines at 33.

Fig. :3 shows an embodiment in which, instead of the cathodes, the ignition electrodes 'of the '4 main discharge tubes are interconnected. In this case also the capacitor 33 may be connected either in the cathode lead of the auxiliary discharge tube 22 or in the common lead of the ignition electrodes 33.

In lieu of the mostly used ignition electrodes as employed in ignitron tubes, it is also possible to use capacitative ignitron electrodes (Sen- .dytron tubes).

In some cases even the small current through the other transformers is deemed undesirable, for example, when any still existing small chance of ignition is to be further reduced and/or these loss currents are to be reduced for economical reasons.

This is achieved by means of a voltage reversing combination of chokes and a transformer, a shown in Fig. 4.

When the discharge path I l becomes conductive the current passes from the plus side of the capacitor 33 by way of primary winding 3!, discharge path I i, cathode 23 and secondary winding 28 to the ignition electrode 8, hence point 35 is positive with respect to the cathode ii. However, a smaller current also flows from the cathode 23 through the secondary winding 38 to the other ignition electrode i so that point 36 also has a given, but lower positive voltage with'respect to the cathode l. This voltage is compensated for as well as possible by means of a transformer 3i having a center tap'33 connected to the cathodes and 5. Disregarding choke 39 for the moment, the positive voltage between point 35 and cathode 5 is also applied to the right half of transformer 37. This voltage is also induced into the left half but reversed in polarity, as shown. Since, however, this voltage exceeds the positive voltage set up at point 38, the compensation voltage is reduced by choke id which, in series with the left half of transformer 37 is likewise connected to the cathode (i and point 36. For considerations of symmetry the size choke t!) is halved and a similar choke 39 is connected in series with the right half of transformer 37 thus ensuring compensation for the two points and 33 relativel to each other. In a three-phase circuit-arrangement, as shown in Figs. 1 to 3, three chokes and a three phase zig-zag transformer may, if desired, be employed in the same manner.

What I claim is:

1. Apparatus for selectively igniting a plurality of main gaseous discharge tubes each of which has an immersed ignition electrode and a cold cathode, the cathodes of said main tubes being interconnected, said apparatus comprising an auxiliary discharge tube provided with a like plurality of anodes and a common cathode to define a separate discharge path between each anode and the common cathode, an ignition circuit coupled to each main tube and including an ignition voltage source, a transformer having first and second windings and a respective discharge path within said auxiliary tube, said first winding being connected in series with said source and said second winding between the ignition electrode of the related main tube and said cathode interconnection, and means to ignite each of said discharge paths thereby to effect ignition of the related main tube, said transformer having a characteristic at which the impedance of the series-connected windings when ignition current flows therethrough is'less than the impedance of either winding inthe absence of ignitioncurrent flow, whereby whenany of the main tubes is ignited accidental ignition of the remaining tubes is prevented.

2. Apparatus as set forth in claim 1 wherein said transformer windings have a winding ratio of substantially 1:1.

3. Apparatus as set forth in claim 1 wherein said transformer becomes saturated when ignition current flows in both windings.

4. Apparatus for selectively igniting a plurality of main gaseous discharge tubes each of which has an immersed ignition electrode and a cold cathode, the ignition electrodes of said main tubes being interconnected, said apparatus comprising an auxiliary discharge tube provided with a like plurality of anodes and a common cathode to define a separate discharge path between each anode and the common cathode, an ignition voltage source, an ignition circuit coupled to each main tube and including a transformer having first and second windings and a respective discharge path within said auxiliary tube, said first winding being connected in series with said source and said second winding between the ignition electrode of the related main tube and said cathode interconnection, and means to ignite each of said discharge paths thereby to effect ignition of the related main tube, said transformer having a characteristic at which the impedance of the series-connected windings when ignition current flows therethrough is less than the impedance of either winding in the absence of ignition current flow, whereby when any of the main tubes is ignited accidental ignition of the remaining tubes is prevented.

5. Apparatus as set forth in claim 4 wherein said ignition source is connected to said cathode interconnection.

6. Apparatus as set forth in claim 4 wherein said ignition source is coupled to the immersion electrodes of all the main tubes.

7. Apparatus for selectively igniting a plurality of main gaseous discharge tubes each of which has an immersed ignition electrode and a cold cathode, the cathodes of said main tubes being interconnected, said apparatus comprising an auxiliary discharge tube provided with a like plurality of anodes and a common cathode to define a separate discharge path between each anode and the common cathode, a series circuit in parallel with the electrode and cathode of each tube and including an inductance and a compensation transformer, an ignition circuit coupled to each main tube and including an ignition voltage source, a transformer having first and second windings and a respective discharge path within said auxiliary tube, said first winding being connected in series with said source and said second winding between the ignition electrode of the related main tube and said cathode interconnection, and means to ignite each of said discharge paths thereby to effect ignition of the related main tube, said transformer having a characteristic at which the impedance of the series-connected windings when ignition current flows therethrough is less than the impedance of either winding in the absence of ignition current flow, whereby when any of the main tubes is ignited accidental ignition of the remainin tubes is prevented.

KOENRAAD DROOGLEEVER FORTUYN.

N 0 references cited. 

